JP2007510606A - Equipment for non-contact transport, handling and storage of parts and materials - Google Patents

Abstract

An apparatus for generating a vibration state by acoustic levitation of an object (1) having at least one surface portion suitable for acoustic levitation, wherein the surface portion floats above a surface that emits sound. In the apparatus, the apparatus has the following features:
A highly rigid support structure (2) having a support structure surface (3) for receiving a force acting perpendicular to the support structure surface (3) by gravity or acceleration of the vibrating object;
A vibrable thin surface element (4) arranged parallel to the support structure surface (3);
The surface element (4) that can vibrate floats in a non-contact manner above the surface (3) of the support structure and the object (1) is above the surface element (4). Generation means for making the vibration state so that it floats (5)
Is a device for generating a vibration state by acoustic levitation of an object.

Description

  The present invention relates to an apparatus for transporting parts or materials in a non-contact or substantially non-contact manner along a transport track. The invention further relates to an apparatus for handling and storing parts or materials in a non-contact or almost non-contact manner.

  Various techniques are known in the prior art for moving or holding parts or materials in a non-contact or nearly non-contact manner. For example, a conveying device using a repulsive force of a magnet or an air cushion is widely used. The air cushion can be generated using a nozzle plate through which air flows. Another technique for generating an air cushion is the use of sound waves.

From US Pat. No. 6,057,037, which is a patent document, a conveying device that operates according to the sound pressure principle is known. Further explanation of this theme, sound pressure and acoustic levitation is given in the following literature:
Non-patent document 1
Non-Patent Document 2.

  The apparatus according to Patent Document 1 has a conveyance rail, and a vibration generator (source) is coupled to the beginning of the conveyance rail, and the vibration generator is the beginning of the conveyance rail so that a traveling wave is generated. Excited. The traveling wave induced in this way diffuses in the transport direction along the transport rail. A device (sink) for converting traveling wave mechanical energy into electrical energy is provided at the end of the transport rail. Thus, this device prevents reflection and thus prevents the traveling wave from reversing.

  If an object is present on the transport rail, the object is moved toward the sink along the transport rail by a moving air cushion generated by traveling waves between the transport rail and the bottom surface of the object to be transported. . As a result of the test, it was possible in principle to transport an object using this apparatus.

  Further structures in the prior art are shown in Patent Document 2, Patent Document 3, Patent Document 4 and Patent Document 5.

  All previously known structures of acoustic levitation in the near-field are based on the fact that the component is supported in a non-contact manner, ie floating above the surface that vibrates and thus radiates the sound. For this purpose, it is necessary to cause vibration on this surface. It is known to those skilled in the art that the vibration characteristics of a solid are mainly determined by the material and its dimensions or shape. For example, if a transport track for transporting flat parts is to be configured for a certain transport system, this transport track must on the one hand be designed as a vibrable system, but on the other hand, on the other hand, the entire transport system. The structural peripheral conditions set by the spatial requirements of Therefore, a device for non-contact transport, storage or handling according to the principle of acoustic levitation has a predetermined geometric shape and pre-set to achieve the vibration characteristics necessary for the occurrence of levitation. Must have a defined dimension and usually have a completely different geometric shape to meet the requirements as a transport track, storage device or holding- or handling device in terms of size or eg weight There is a target conflict with what should be.

To clarify this problem, it is suggested, for example, that the transport rail that generates the air cushion by the air nozzle is not subject to this restriction, because the air passes to the nozzle via a duct that can be formed almost freely. This is because this duct can also be arranged at almost a freely selectable position. However, this system cannot be used generally because the unavoidable fluid flow effect in gaseous media is not desirable for certain technologies.
US Pat. No. 5,810,155 German Patent Application Publication No. 19916922 German Patent Application Publication No. 1916923 German Patent No. 19916856 specification German Patent No. 19916872 Lierke, E .; G. : Vergleichend Bechtung zur beruehrungslosen Positionierung von Einzeltropfen in aerodynamischen, akustischen und elektrischen Kraftfeld. In: Forschung im Ingenieurwesen, Vol. 61 (1995) 7/8, p. 201-216 Lierke E.M. G. Akustische Positionionung-Ein umfassender Ueberblick weber Grandgen und Annwengen. In: Acoustica 82 (1996), p. 220-237

  Accordingly, an object of the present invention is to provide a levitation technique by acoustic vibration that avoids the drawbacks of the above technique.

  This problem is solved with the device according to claim 1 and the method according to claim 17.

  An apparatus has been provided for generating a vibrational state of an object by acoustic levitation, in which the object must have at least one surface portion suitable for acoustic levitation. A hard surface (reflecting sound) is advantageous, in which case the hard surface part floats above the acoustically emitting surface. However, it is also possible to float a powdered material or a granular material, but in this case a completely non-contact floating state cannot be achieved. According to the invention, this device has a highly rigid support structure. The support structure can be made of a freely selectable material such as metal, plastic, glass, ceramics or composite material. The production method can also be freely selected, so for example casting and injection molding methods are also applicable. A crucial prerequisite is that the support structure is suitable for absorbing forces acting on the surface of the support structure due to the gravity or acceleration of the vibrating object. Furthermore, the support structure surface must be material stable against dynamic loading due to levitation sound waves used for the levitation of the object or material. A thin planar element that can vibrate is arranged parallel to the surface of the support structure. In order to vibrate the surface element such that the surface element floats in a non-contact manner above the surface of the support structure, vibration generating means is further provided. The vibration can be generated in various ways, for example by external excitation or internal excitation. As materials for the surface elements, as long as they are externally excited, basically all raw materials with high plasticity and hardness, such as thin steel plates, thin plates made of non-ferrous metal alloys, plastics or also composite materials, Is appropriate. As a material for internal excitation, for example, a film that uses the inverse piezoelectric effect to generate vibration can be used. The shape of the support structure surface need not necessarily be flat.

  By separating the functions of “support” and “vibration” according to the present invention, a paradigm change was achieved in the acoustic levitation technology. For example, it has become possible for the first time to construct a transport trajectory without considering its vibration behavior. It is therefore possible to optimize the transport trajectory with respect to various peripheral conditions such as weight, resistance to aggressive media, material costs, etc. Designers are also limited in the selection of materials for vibrating surface elements, and they have a wide choice of materials and techniques.

  There are particular advantages to applications or techniques with standardized spatial proportions. A typical technique for this is wafer fabrication. Thus, the present invention makes it possible for the first time to provide an apparatus that can be adapted to the predetermined spatial ratio of this technology.

  According to claim 2, the surface element capable of vibration is a metal sheet or a plastic sheet having comparable vibration characteristics. The vibration generating means is a device for generating dynamic vibration transmitted to the metal thin plate or plastic plate.

  According to claim 3, the surface element is a piezoelectric film excited by electricity. Films that utilize the inverse piezoelectric effect to generate mechanical thickness vibrations are known to those skilled in the art, and therefore no inventive activity is required to appropriately select a piezo film for the anticipated industrial application. The advantage of this film is in particular that the vibration frequency can be adjusted electrically over a very wide range.

  According to claim 4, the surface element is a material film excited by magnetostriction. The occurrence of elastic deformation of magnetostrictive materials in a magnetic field is also known to those skilled in the art. In this application, the electromagnet is preferably incorporated in a support structure made of a nonmagnetic material.

  According to claim 5, the surface element is a material film excited by electrostriction, in which case the material has electrostrictive properties and is provided with a device for excitation by electrostriction.

  According to claim 6, the excitation of vibrations is performed by a mechanically rigid coupling device. Particularly advantageous is the ability to excite a plurality of surface elements simultaneously with a single device.

  According to the seventh aspect, the vibration is not excited directly but via the intermediate medium.

  According to claim 8, the intermediate medium is gaseous, that is, the flowing gas contacts the edge of the surface element, for example, and generates vibration.

  According to the ninth aspect, the intermediate medium is in a liquid state, that is, the flowing liquid comes into contact with, for example, the edge of the surface element to generate vibration.

  According to claim 10, the surface element is controlled to vibrate at various frequencies and / or amplitudes. By this measure, for example, it is possible to cause an excessive increase in amplitude that forcibly changes the direction of an object that is linearly moved in one conveyance section.

  According to the eleventh aspect, a plurality of surface elements are arranged and can be selectively controlled. For example, when a plurality of surface elements are arranged on the same plane and in the direction of the conveyance section in one conveyance section, the direction can be forcibly changed similarly by different control of the surface elements. As a result, a branch function is achieved.

  According to the twelfth aspect, at least one intake port or gas suction port is provided on the surface of the support structure. At least one hole is also arranged in the surface element, this hole being not exactly facing the suction port. When the suction port is depressurized, the surface element is pressed onto the surface of the support structure by the outside air pressure. In this case, the thin and flexible surface element is close to the outer shape of the surface of the support structure and is thereby fixed in position. However, direct contact with the surface of the support structure is prevented by the vibrational movement of the surface element, so that the surface element also floats parallel to the surface of the support structure in this embodiment. Since the surface element is also provided with at least one hole, this embodiment is suitable, for example, as a gripper, since a flat part can be caught from above, i.e. sucked.

  If the surface element is not provided with holes, this embodiment is particularly suitable for forming a transport track without a flat surface.

  According to claim 13, protection of the patent of the transport device in which the device according to claims 1 to 12 is used is claimed, in which case transport is defined as a horizontal or slightly inclined track from A to B. This refers to the movement of an object.

  According to claim 14, the patent protection of the gripping device in which the device according to claims 1 to 12 is used is claimed, in which case gripping means picking up, transporting and unloading parts. Such an apparatus can be incorporated into, for example, an articulated robot.

  According to claim 15, protection of the storage and holding device patent in which the device according to claims 1 to 12 is used is claimed. Using this, for example, it is possible to temporarily store the part in a non-contact manner until the part is subsequently sent to the next process step.

  According to claim 16, there is provided a bearing in which the shaft rotates in a contactless manner under use of the device according to claims 1-12. For this purpose, the support structure is formed as a tube. The face element is close to the inner wall without contacting the inner wall of the tube.

According to claim 17, a method for generating a vibration state by acoustic levitation for an object having at least one surface portion suitable for acoustic levitation, wherein the surface portion radiates acoustically. Protection of the patent of the method floating above the surface is claimed, in which case the method comprises the following processing steps:
Providing a rigid support structure having a support structure surface for receiving forces acting perpendicular to the support structure surface by gravity or acceleration of a vibrating object;
The provision of vibrated thin surface elements arranged parallel to the surface of the support structure;
Preparation of vibration generating means for bringing the thin surface element capable of vibration into a vibration state in which the surface element floats above the surface of the support structure in a non-contact manner and the object floats above the surface element. Have

  The invention will now be described in detail by way of example with reference to the accompanying schematic drawings.

  FIG. 1 is a side view of a horizontal transport track on which a flat disk 1 can be carried in the direction of the arrow. The support structure 2 having the support structure surface 3 is designed so that the weight of the disk 1 or other influences do not deform the support structure 2, ie the support structure 2 is made rigid. Yes. A spring steel sheet 4a having a thickness of 0.05 mm is arranged above the support structure surface 3, and this spring steel sheet rests on the support structure surface 3 in a stationary state. In the part A, the sheet is mechanically rigidly joined to the vibration generator 5. When vibration is generated in the spring steel sheet 4 using a vibration generator at a frequency of 30 kHz, the sheet is released from the support structure surface 3 and floats above the surface in a contactless manner at a distance of about 0.02 mm. The required frequency is selected by those skilled in the art in view of the dimensions and material properties of the sheet. When a wafer is placed on the sheet, it floats in a non-contact manner and can be moved by various acceleration means known in the prior art. Such acceleration means is, for example, irradiation by gravity or sound in an inclined transport track.

  FIG. 2 shows the same structure as FIG. Instead of the spring steel sheet, a piezo film 4b whose surface is metallized is used. Piezofilms are of high rigidity ceramic type and of polymer material. An electrical connection connected to a frequency generator is arranged on this metallized surface. The advantage of polymer piezo films is a wide frequency range that can be freely selected for thickness vibration.

  FIG. 3 also shows the same structure as FIG. Instead of the spring steel sheet, a film 4c made of magnetostrictive material is used. A solenoid 5 is incorporated in a plastic support structure so that an alternating magnetic field generated by an electric current causes the film to vibrate.

FIG. 4 shows a top view of the transport track according to FIG. 1, however, it is provided with _three spring steel sheets 4 ₁ , 4 ₂ , 4 _{3 which} are controlled separately. This device can be used as a guide or as a branch. When the sheets 4a and 4c vibrate more strongly than the sheet 4b, the disk 1 is moved toward the center and guided without an outer stopper along the center of the track. When the sheet 4a vibrates more strongly than the sheet 4b, and similarly the sheet 4b vibrates more strongly than the sheet 4c, the disk slides from the track in the arrow direction R, and as a result, a branch function is realized.

FIG. 5 shows a holding device for three disks to be held or stored in a stack. The support structure has three stages, and the sheets 4 ₁ , 4 ₂ , 4 ₃ are connected to the vibration generator via the coupling device 6. With this device, the disk can be temporarily stored until the next process step.

  FIGS. 6 a and 6 b show a side view and a top view, respectively, of a gripping device provided with a support structure 2 a having a suction hole 7. A porous plate 8 is disposed above the support structure. When starting this gripping device, it is preferable to first switch on the vibration generator in order for the perforated plate 8 to reach a vibrating state. Next, the suction hole 7 is depressurized, and as a result, the perforated plate is pressed onto the surface of the support structure. That is, by this suction, the perforated plate 8 that vibrates at a distance is fixed facing the surface of the support structure. When the disk 1 floats on the porous plate 8 in a non-contact manner, the disk is fixed in the same manner as the porous plate 8 is fixed. This gripping device can be used for articulated robots, so that the disc can be moved in a freely selectable spatial trajectory. By forming the flow conditions specially, it is possible to eliminate the need for fixing the disk on the side.

  FIG. 7 shows a bearing in which the shaft rotates without contact. For this purpose, the support structure is formed as a tube 10. The surface element 4 is close to the inner wall of the tube 10.

  Obviously, a closed (tube-shaped) conveying section for the material can also be constructed according to this principle, which allows a very slight frictional resistance at the tube wall, for example in the case of powdered material.

FIG. 1 is a diagram showing a first embodiment of the present invention. FIG. 2 is a diagram showing a second embodiment of the present invention. FIG. 3 is a diagram showing a third embodiment of the present invention. FIG. 4 is a diagram showing a fourth embodiment of the present invention. FIG. 5 is a diagram showing a fifth embodiment of the present invention. 6a and 6b are views showing a sixth embodiment of the present invention. FIG. 7 is a diagram showing a seventh embodiment of the present invention.

Claims (17)

An apparatus for generating a vibration state by acoustic levitation of an object (1) having at least one surface portion suitable for acoustic levitation, wherein the surface portion floats above a surface that emits sound. In the device,
The device has the following features:
A highly rigid support structure (2) having a support structure surface (3) for receiving a force acting perpendicular to the support structure surface (3) by gravity or acceleration of the vibrating object;
A vibrable thin surface element (4) arranged parallel to the support structure surface (3);
The surface element (4) that can vibrate floats in a non-contact manner above the surface (3) of the support structure and the object (1) is above the surface element (4). Generation means for making the vibration state so that it floats (5)
A device for generating a vibration state by acoustic levitation of an object, characterized by comprising:   The thin surface element (4) capable of vibration is a metal thin plate (4a) or a plastic plate having comparable vibration characteristics, and the vibration generating means is a device for generating mechanical vibration, which is a vibration device. The device according to claim 1, wherein the device is coupled to the sheet metal or plastic plate such that is transmitted to the sheet metal or plastic plate.   2. A device according to claim 1, characterized in that the oscillating thin planar element is a piezoelectric film (4b) which can be excited by electrostriction.   The vibrated thin surface element is a material film (4c) that can be excited by magnetostriction, wherein the material has magnetostrictive properties and is equipped with a device for excitation by magnetostriction. The apparatus according to claim 1.   The vibrated thin surface element (4) is a material film that can be excited by electrostriction, wherein the material has electrostrictive properties and is equipped with a device for excitation by electrostriction. The apparatus according to claim 1.   The device according to claim 2, wherein the coupling is performed by a mechanically rigid coupling device.   The apparatus according to claim 2, wherein the coupling is performed via an intermediate medium.   8. A device according to claim 7, characterized in that the intermediate medium is gaseous.   8. A device according to claim 7, characterized in that the intermediate medium is liquid.   10. Device according to any one of the preceding claims, characterized in that the oscillating thin planar element (4) is controlled to oscillate at various frequencies and / or amplitudes.   Device according to any one of the preceding claims, characterized in that a plurality of surface elements (4) are arranged and can be selectively controlled.   At least one intake port or gas suction port (7) is provided on the surface of the support structure, and at least one hole is arranged in the surface element (8). 12. The object is adjusted so that an object is sucked by the hole and held at a certain distance from the surface of the surface element by the vibrating air film of the surface element. The apparatus as described in any one of.   A transport apparatus in which the apparatus according to any one of claims 1 to 12 is used.   Gripping device in which the device according to any one of claims 1 to 12 is used.   Storage and holding device in which the device according to any one of the preceding claims is used.   A bearing in which the device according to any one of the preceding claims is used, wherein the support structure is a tube (10). A method for generating a vibration state by acoustic levitation of an object (1) having at least one surface portion suitable for acoustic levitation, wherein the surface portion floats above a surface that emits sound. In said method,
The method comprises the following processing steps:
Providing a highly rigid support structure (2) having a support structure surface for receiving a force acting perpendicularly to the support structure surface (3) by gravity or acceleration of a vibrating object;
The provision of a vibratable thin surface element (4) arranged parallel to the support structure surface (3);
The vibrating thin surface element (4) has the surface element (4) floating above the surface of the support structure in a non-contact manner, and the object (1) is floating above the surface element (4). An apparatus for generating a vibration state by acoustic levitation of an object, characterized in that it has provision for vibration generation means (5) for making such a vibration state.

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